Aerodynamic bicycle rim and wheel

ABSTRACT

Embodiments described herein provide aerodynamic bicycle rims and wheels. Embodiments can include a bicycle rim that is wider than the width of the tire proximate to the outer edge of the rim and is shaped so that there is a tangent line tangent to the rim and the tire. The tangent line can be tangent to the rim on the sidewall or elsewhere on the rim. The widest part of the rim can be radially inward from the outer edge of the rim or elsewhere on the rim and the tangent line can be tangent at the widest part of the rim or elsewhere on the rim.

RELATED APPLICATIONS

This application is a continuation of, and claims a benefit of priorityunder 35 U.S.C. 120 of the filing date of U.S. patent application Ser.No. 12/553,026 filed Sep. 2, 2009, entitled “Aerodynamic Bicycle Rim andWheel”, which in turn claims the benefit of priority under 35 U.S.C.§119(e), to U.S. Provisional Patent Application No. 61/185,489 filedJun. 9, 2009, entitled “Aerodynamic Bicycle Rim and Wheel”, by Hed etal., which is hereby fully incorporated by reference herein.

TECHNICAL FIELD

This application is related to bicycle wheels. More particularly, thisapplication describes systems bicycle rims and wheels with increasedstall angles and decreased drag.

BACKGROUND

Drag or wind resistance is a major force acting against the movement ofa cyclist. Greater drag requires a cyclist to exert more energy tomaintain or increase speed. This is particularly important in bicycleracing in which riders must conserve energy over long distances andraces can be won or lost in a matter of seconds.

One way in which to reduce drag is to make components more aerodynamic.In the past 20 years, new designs have been developed to reduce the dragcaused by airflow over the wheels. Some manufacturers have produced rimsso that the rim and tire form an oval (elliptical) shape with the rimbeing narrower than the tire at the outer edge of the rim and widestpart of the rim occurring at the minor axis of the ellipse. This shapehas been modified in some products to have parallel braking surfacesnear the outer portion of the rim.

Such wheels are made with the assumption that the airflow will behead-on to the cyclist. In practice, however, side winds cause air flowto come from angles to the side of the wheel, causing previous wheels tostall and lose aerodynamic efficiency.

SUMMARY

Embodiments described herein provide aerodynamic bicycle rims andwheels. One embodiment can include an aerodynamic bicycle rim having acircumferential tire mounting surface on an outer side of the bicyclerim forming a tire seat to seat a tire. The rim can also include a setof sidewalls extending from a nose of the bicycle rim to a transition tothe circumferential tire mounting surface to form a bicycle rim bodyhaving a cross-section that is wider than the width of the tireproximate to the outer edge of the bicycle rim. The bicycle rim isoperable to seat the tire so that there is a tangent line tangent to thetire and tangent to a sidewall of the bicycle rim.

The widest portion of the bicycle rim can occur anywhere along the rimincluding at the outer edge of the rim, at the outer part of thesidewall (at the beginning of the transition from the sidewall to thetire mounting surface) or at another point of the rim. The cross-sectionof the wheel and rim can be substantially elliptical or asymmetrical.The tangent line can be tangent to the rim on the sidewall or anotherportion of the rim and can be tangent to the rim at the widest portionof the rim or other portion of the rim. By way of example, but notlimitation, example tangent angles range from 7-17 degrees from thelateral centerline. The shape of the rim can be selected so that the rimand tire have a selected stall angle. In one embodiment, the stall anglecan be up to about 20 degrees. In particular embodiments, the rim shapecan be selected to exhibit a stall angle of 8-19.5 degrees.

Another embodiment can comprise a bicycle rim having circumferentialtire mounting surface on an outer side of the bicycle rim forming a tireseat to seat a tire and a set of sidewalls, with the sidewalls from anose of the bicycle rim to a transition to the circumferential tiremounting surface to form a bicycle rim body. The bicycle rim is widerthan the width of the tire proximate to the outer edge of the bicyclerim. Additionally, the bicycle rim can be shaped so that there is atangent line tangent to the tire and tangent to the bicycle. Thecross-section of the bicycle rim and tire can be asymmetrical about acenterline of the cross-section.

Embodiments described herein provide an advantage over previous bicyclerims and wheels by providing increased stall angles for a similar depthrim.

Embodiments described herein, provide another advantage providingreduced drag.

For bikes, such as mountain bikes, in which aerodynamics is are less ofa concern, embodiments of rims described herein can provide otheradvantages such as potentially reducing the likelihood of pinch flats (aflat tire caused when a hard object, such as a rock, causes a tire tobottom out on the rim pinching the inner tube of the tire against therim).

Embodiments described herein can also allow more adhesive to be used toadhere a tire to the rim and provide more side support for the tire,thereby decreasing the likelihood of rollouts and increasing safety.

BRIEF DESCRIPTION OF THE FIGURES

A more complete understanding of the embodiments and the advantagesthereof may be acquired by referring to the following description, takenin conjunction with the accompanying drawings in which like referencenumbers indicate like features and wherein:

FIG. 1 is a diagrammatic representation illustrating meteorologicalwind, apparent wind and yaw;

FIG. 2 is a diagrammatic representation of one embodiment of a rim;

FIG. 3 is a diagrammatic representation of one embodiment of across-section of a rim and tire;

FIG. 4 is a diagrammatic representation of another embodiment of across-section of a rim and tire;

FIG. 5 is a diagrammatic representation of another embodiment of across-section of a rim and tire;

FIG. 6 is a diagrammatic representation of another embodiment of across-section of a rim and tire;

FIG. 7 is a diagrammatic representation of another embodiment of across-section of a rim and tire;

FIG. 8 is a diagrammatic representation of another embodiment of a crosssection of a rim and tire;

FIG. 9 is a diagrammatic representation of another embodiment of across-section of a rim and tire;

FIG. 10 is a diagrammatic representation of another embodiment of across-section of a rim and tire;

FIG. 11 is a diagrammatic representation of another embodiment of across-section of a rim and tire;

FIGS. 12A, 12B, and 12C are diagrammatic representations of embodimentsof rim noses;

FIG. 13 is a chart illustrating test data for embodiments of rims;

FIG. 14 illustrates an embodiment of a disc wheel;

FIG. 15 illustrates another embodiment of a wheel.

DETAILED DESCRIPTION

The disclosure and various features and advantageous details thereof areexplained more fully with reference to the exemplary, and thereforenon-limiting, embodiments illustrated in the accompanying drawings anddetailed in the following description. Descriptions of known startingmaterials and processes may be omitted so as not to unnecessarilyobscure the disclosure in detail. It should be understood, however, thatthe detailed description and the specific examples, while indicatingseveral embodiments, are given by way of illustration only and not byway of limitation. Various substitutions, modifications, additionsand/or rearrangements within the spirit and/or scope of the underlyinginventive concept will become apparent to those skilled in the art fromthis disclosure.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,product, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, product,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

Additionally, any examples or illustrations given herein are not to beregarded in any way as restrictions on, limits to, or expressdefinitions of, any term or terms with which they are utilized. Insteadthese examples or illustrations are to be regarded as being describedwith respect to one particular embodiment and as illustrative only.Those of ordinary skill in the art will appreciate that any term orterms with which these examples or illustrations are utilized encompassother embodiments as well as implementations and adaptations thereofwhich may or may not be given therewith or elsewhere in thespecification and all such embodiments are intended to be includedwithin the scope of that term or terms. Language designating suchnon-limiting examples and illustrations includes, but is not limited to:“for example,” “for instance,” “e.g.,” “in one embodiment,” and thelike.

Embodiments described herein include bicycle rims and wheels thatprovide increased aerodynamics compared to previous bicycle rims andwheels. In particular, embodiments described herein provide bicycle rimsand wheels that exhibit increased stall angles and reduced drag over agreater range of wind angles in comparison to previous rims and wheels.

Before proceeding, it may be helpful to define several phrases used whendiscussing the aerodynamics of bicycles. Meteorological (true) windangle: wind angle experienced by a stationary observer. In thisdefinition, the direction the observer faces is 0 degrees.Meteorological wind is the angle from which the wind is blowingnaturally. Apparent wind: air flow felt by the cyclists because of thecombination of the meteorological wind and the movement of the cyclist.Apparent wind angle: the angle of the actual flow of air acting on thewheels of a moving cyclist. Because the observer (cyclist) is moving,the apparent wind is the relative angle of the wind in relation to theobserver. Yaw angle: the angle of airflow when the wheel orientationfront to back is zero degrees. Assuming a moving cyclist, yaw angle isthe same as apparent wind angle. Stall angle: the yaw angle at whichairflow cannot remain laminar as it both passes over and exits the wheelsurface. Laminar airflow is advantageous and increases the aerodynamicefficiency of the wheel and results in faster rider speeds for a giveneffort. Non-laminar airflow is turbulent and decreases aerodynamicefficiency. Non-laminar airflow slows a rider's speed at a given amountof effort.

FIG. 1 illustrates the concepts of apparent wind and yaw (apparent windangle). Apparent wind is the wind experienced by an object from thecombination of the object moving through air and meteorological windblowing on the object. In FIG. 1, a cyclist 100 is riding in direction105 at 27 mph and the wind indicated at 115 is blowing at 10 mph atangle 120, in this example −30° to cyclist 100 (for purposes of thisdisclosure, negative angles are to left of the bicycle and positiveangles are to the right of the bicycle). The wind felt by cyclist 100 isa combination of airflow created by the cyclist's movement and themeteorological wind. In this example, the bicycle will encounter anapparent wind 122 of 36 mph at an apparent wind angle 125 (also referredto as yaw) of −8°. If, the cyclist slows down to 24 mph, but themeteorological wind stays the same, the apparent wind will be 33 mphwith an apparent wind angle of −8.7°. This shift in apparent wind angleoccurs because the meteorological wind becomes a relatively largercomponent of the apparent wind.

The velocity of apparent wind can be characterized by EQN 1 as follows:A=((W*(cos(a)−V)^2+(W*sin(a))^2)^0.5  [EQN 1]where:

-   W=meteorological wind speed-   a=angle of meteorological wind to rider where 0=headwind and    180=tailwind-   V=velocity of the rider-   The apparent wind angle or yaw can be characterized by:

$b = {{arc}\;{\cos\left( \frac{{W\;\cos\; a} - V}{\sqrt{\left( {{W\;\cos\; a} - V} \right)^{2} + \left( {W\;\sin\; a} \right)^{2}}} \right)}}$

-   where b=apparent wind angle.

When a bicycle is in motion, airflow over a bicycle's wheels resultsfrom the apparent wind. For wheels that are designed to be aerodynamiconly in a head wind, the airflow over the wheel will be relativelysmooth for angles close to head-on, but become turbulent at greaterangles, thereby increasing drag. The angle relative to the wheel atwhich this transition from attached to disturbed flow occurs is referredto as the stall angle. Apparent winds having a yaw greater than thestall angle result in increased drag.

Embodiments of bicycle wheels described herein can exhibit increasedstall angles and therefore maintain aerodynamic efficiency through agreater range of conditions. Various embodiments of bicycle rimsdescribed herein can be shaped to seat a tire of a selected size orrange of sizes. The rim is shaped so that the rim is wider than the tireat or proximate to the outer edge of the rim. This allows the tire toact as a fairing for the wheel to promote attached airflow along therim. Additionally, the rim can be shaped so that there is a tangent linethat is tangent to the tire and a sidewall of the rim. The tangent linecan be tangent to the sidewall at any desired point along the sidewallof the rim including at the widest part of the rim or other point alongthe sidewall. The widest part of the rim can occur at any point in therim, including, but not limited to, the center of the cross-section ofthe rim, the center of the cross-section of the rim and tire, the innerthird or outer third of the rim. The wheel with the tire mounted can beasymmetrical or symmetrical about the centerline of the rim and tire.Asymmetry can result, in various embodiments, from the placement of thewidest portion of the rim, the nose shape, the sidewall shape or acombination of factors. In other embodiments the wheel can besymmetrical about the centerline of the rim and tire.

In another embodiment, the rim can be shaped so that there is a tangentline tangent to the tire and tangent to the rim at any point on the rimincluding the sidewalls, the tire seating surface, the transitionbetween the tire seating surface and the sidewall or other point on therim. The tangent line can be tangent to the rim at the widest part ofthe rim or another portion of the rim.

Embodiments described herein can be applied to with wire spokes, wheelswith a smaller number of aerodynamic spokes and disc wheels. The wheelscan be used for any type of bicycle including road bikes, mountainbikes, recumbent bikes or other bikes. Rims can be shaped to have adesired stall angle.

FIG. 2 is a diagrammatic representation of one embodiment of a bicyclerim 200 having an annular body extending radially from radially inneredge 205 to a radially outer edge 210. A tire can mount to rim 200 at acircumferential tire mounting surface 215. Sidewall 220 extends frominner edge 205 to tire mounting surface 215. The transition 225 fromsidewall 220 to tire mounting surface 215 can be a square corner, anarea of decreased radius compared to the remainder of sidewalls 220 orhave another shape to transition from sidewalls 220 to circumferentialtire mounting surface 215. The sidewalls 220 can form a nose 230proximate to inner edge 205. Sidewalls 220 can include any desiredfeatures including, but not limited to dimpling, parallel brakesurfaces, flat brake surfaces, curved brake surfaces or other features.As discussed in more detail below, rim 200 can be shaped to increase thestall angle of a bicycle wheel.

FIG. 3 is a diagrammatic representation of one embodiment of across-section of bicycle wheel 235 comprising rim 200 and tire 240. Tiremounting surface 215 forms a tire bed 250 in which tire 240 seats.Additionally, tire mounting surface 215 can form a groove 255 in whichstitching of tire 240 can rest. Rim 200 can have a depth “d” and beconfigured to fit tires of a particular size or range of sizes with rim200 being wider than the width of tire 240 at or proximate to the outeredge 210. The depth of rim 200 can be selected as desired. Typical rimdepths for non-disc wheels range from 30 mm-110 mm, though other depthscan be used.

The shape of rim 200 can be selected so that there is a tangent line 270from tire 240 to sidewall 220. Tangent line 270 can be tangent to rim200 at any point along sidewall 220. According to one embodiment,tangent line 270 can be tangent to sidewall 220 at the widest part ofrim 200. For example, the widest part of rim 200 can occur at i) theradial outer third of rim 200, ii) the radial inner third of rim 200,iii) the radial centerline of rim 200, iv) the radial centerline of thecross section of rim 200 and tire 240 or v) other portion of wheel 240.

In the embodiment of FIG. 3, wheel 235 is symmetrical about axis 275 butnot symmetrical about axis 280. This asymmetry results because thewidest portion of rim 200 does not fall near axis 280 and nose 230 doesnot have substantially the same radius as tire 240. Consequently, wheel235 does not have a substantially elliptical or otherwise symmetricalshape about axis 280. In other embodiments, rim 200 can have asubstantially symmetrical shape about both axis 275 and axis 280. Suchsubstantially symmetrical shapes include, but are not limited to,elliptical (oval) and lenticular shapes.

FIG. 4 is a diagrammatic representation of another embodiment of a crosssection of a wheel 400 comprising rim 405 and a tire (three differentsizes of tires are illustrated, represented at 410′, 410″ and 410′″).Rim 405 can have a depth “d” from an outer edge 470 to inner edge 415.Tire seating surface 420 can be shaped to receive the tire in a tire bed425. In one embodiment, tire bed 425 can include a groove 430 in whichstitching of the tire rests. Tire bed 425 can be shaped to fit a tire ofa selected size or tires in a range of sizes.

Rim 405 is shaped so that the width of rim 405 at or proximate to theoutermost radial edge 470 of rim 405 is wider than the width of the tire(e.g., at a portion of the rim that overlaps the tire bed).Additionally, rim 405 is shaped so that there is a line tangent to thetire (three different tangent lines are illustrated as tangent lines440′, 440″ and 440′″ for tires 410′, 410″ and 410′″) and tangent tosidewall 435. In one embodiment, the tangent line is tangent to rim 405further outward than the widest portion of rim 405 radially outward fromthe widest portion of rim 405 (represented at 437). In otherembodiments, the tangent line can be tangent at the widest part of rim437. The widest portion of rim 405 can be at a desired location such asat the outermost radially outer third of rim 405 (including at theradially outer edge 470 of rim 405) the radial centerline of wheel 400(near the transverse centerline of the cross section of the rim and tireindicated at line 475), the centerline of rim 405, the radially innerthird of rim 405 or other selected location. In the example of FIG. 4,the widest portion of rim 405 is widest at the radial outer third of rim405. As shown in FIG. 4, the widest portion of the rim indicated at 437occurs closer to the tire bed than to the centerline 475 of the crosssection of the rim and tire. The widest portion, in this embodiment,also occurs closer to the tire bed than to the centerline of rim 405.While the example of FIG. 4 has an asymmetrical shape about line 475with the widest portion of rim 405 located away from the centerline 475and nose 480 having a diameter that is smaller than the width of thetire, other embodiments of wheel 400 can be substantially elliptical orhave other symmetrical shapes. Furthermore, in FIG. 4, the distance fromthe tire bed to the nose is greater than the width of the tire and morespecifically, in the example of FIG. 4, greater than twice the width ofthe tire.

FIG. 4 illustrates tangent lines 440′, 440″ and 440′″ for differentsized tires 410′, 410″ and 410′″. As one example, line 440′ for tire410′ has an angle of 14° to the lateral centerline, line 440″ has anangle of 12° to the lateral centerline and line 440′″ for tire 410′″ hasan angle of 9° to the lateral centerline. For a given rim shape,increasing the angle of the tangent line will typically increase thestall angle of wheel 400. Consequently, smaller width tires can lead toincreased stall angles. It should be noted that the example angles areprovided by way of example and not limitation.

In the embodiment of FIG. 4, a majority of the tire is shown as exposedabove the outermost portion of rim 405. However, the tire is seateddeeper than with traditional rims leading to a more unified aerodynamicshape. By way of example, but not limitation, 20-80% of the tire can beseated, leaving 80-20% of the tire exposed past the outermost edge ofthe rim. Seating the tire more deeply will increase the tangent angle,thereby increasing stall angle. Additionally, seating the tire moredeeply can allow more adhesive to be used between the tire and tire bed425 and allow tire bed 425 to provide more support for the tire. Thisreduces the likelihood of the tire rolling out of bed 425 during hardcornering, thereby decreasing the likelihood of accidents.

According to one embodiment, the area of sidewall 435 under the tangentline (shown at 465) can have a tapered or curved shape to promoteattached flow. In other embodiments, area 465 may be straight or includea transition to surface 420. The area closer to inner side 415 can haveany desired shape. According to one embodiment, sidewalls 435 can have acurved shape to maintain attached or smooth flow for as long aspossible. In such an embodiment, sidewall 435 can be curved where thebicycle's brake pads contact rim 405. This can lead to better braking asthe brake pads wear into a curved shape having larger braking area. Inother embodiments, sidewalls 435 can have straight braking surfaces.

FIG. 5 is a diagrammatic representation of a cross section of anotherembodiment of a wheel 500 having rim 505 and a tire (three differentsizes of the tire are represented by tires 510′, 510″ and 510′″). Rim505 can be shaped to be wider than the tire at or proximate to theradially outer edge of rim 505 and to be widest radially closer to thetire bed than the centerline of the cross section and to be widestradially closer to the tire bed than the centerline of rim 505.Additionally, rim 505 can be shaped so that there is a tangent linetangent to the tire and sidewall 525 (tangent lines from tires 510′,510″ and 510′″ to sidewall 525 are shown by 520′, 520″ and 520′″respectively). The tangent line can be tangent to sidewall 525 at thewidest portion of rim 505 or at some other point along sidewall 525. InFIG. 5, for example, the tangent line is tangent to rim 505 radiallyoutward on sidewall 525 from the widest part of rim 505 (represented atline 530). As in the previous examples, the widest portion of rim 500 islocated away from transverse centerline 535 causing rim 500 to beasymmetrical. In other embodiments, however, rim 500 can besubstantially symmetrical about the transverse centerline. Furthermore,in FIG. 5, the distance from the tire bed to the nose is greater thanthe width of the tire and more specifically, in the example of FIG. 5,greater than three times the width of the tire.

Testing of various embodiments has shown that the stall angle can be atleast the tangent angle and the stall angle increases as the depth ofthe rim depth of the rim increases. As one example, one embodiment of a60 mm wheel with a 12.5 degree tangent angle may exhibit a stall angleof 15 degrees while a 90 mm rim with a 12.5 degree tangent angle mayexhibit a stall angle of 16 degrees. Thus, if tangent lines 520′, 520″and 520′″ have angles as tangent lines 440′, 440″ and 440′″ of FIG. 4,wheel 500 will have a higher stall angle than wheel 400 for each tangentangle. The amount of increase in stall angle due to depth decreases asthe tangent angle increases.

FIG. 6 is a diagrammatic representation of a cross section of anotherembodiment of a wheel 600 having a rim 605 with a tire 610 seated intire bed 615. Rim 605 is shaped so that there is tangent line tangent totire 610 and the sidewall of rim 605. In the embodiment of FIG. 6, theouter edge 620 of rim 605 has a width that is approximately equal to thewidth of tire 610 (as shown by line 625). However, rim 605 is shapedsuch that rim 605 is wider than the width of tire 610 proximate to edge620 at a point that overlaps tire bed 615 as shown by line 630. Thus,even if the very outer edge 620 of rim 605 is not wider than the widthof tire 610, rim 605 is still wider than tire 610 near outer edge 620.In one embodiment, rim 605 can be wider than tire 610 at any point thatoverlaps tire bed 615. In other embodiments, rim 605 can be wider thantire 610 within 2 mm or less of the outer edge of rim 605.

FIG. 7 is a diagrammatic representation of a cross section of anotherembodiment of a wheel 700 having a rim 705 with a tire 710 seated intire bed 712. According to one embodiment, rim 705 can be shaped so thatrim 705 is wider than the width of tire 710 proximate to outer edge 717and so that there is a tangent line 715 from tire 710 to rim 705. Thetangent line 715, in the example of FIG. 7, is tangent to rim 705 at theradially outer part of sidewall 720 where the transition 725 to thecircumferential tire seating surface begins. Additionally, in theembodiment of FIG. 7, the widest portion of the rim 705, represented byline 730, occurs near outer edge 717 so that the widest area of rim 705overlaps tire bed 712. While tangent line 715 is tangent to rim 705 atthe widest part of rim 705, tangent line 705 can be tangent elsewhere onrim 705.

FIG. 8 is a diagrammatic representation of a cross section of anotherembodiment of a wheel 800 comprising a rim 805 seating a tire 810. Rim805 is wider than wheel 810 proximate to the outer edge (represented atline 807) at a portion of rim 805 that overlaps the tire bed.Additionally, rim 805 is widest radially outward of the centerline ofrim 805 (represented at line 809) but more inward than the centerline ofthe cross section of rim 805 and tire 810 as a whole (represented atline 811). Rim 805 is also shaped so that there is a tangent line 815tangent to tire 810 and the sidewall 820 of rim 805, the transition 830from the sidewall 820 to the tire seating surface or other point on rim805. Tangent line 815 can be tangent to rim 805 at the widest portion ofrim 805 or another portion of rim 805.

According to one embodiment, sidewall 820 includes substantially flatbraking surface 830. From the perspective of FIG. 8, braking surface 830can be vertical or may taper outward so that rim 805 becomes wider.Sidewall 820 can also include a curved or otherwise shaped section 835.According to one embodiment, braking surface 830 can extend fromtransition 825 to the widest portion of rim 805. In other embodiments,sidewall 820 can bow out after braking surface 830. Wheel 800, in theembodiment illustrated, is not substantially elliptical as the widestpart of rim 805 is offset from centerline 809 and nose 835 is not shapedto match the radius of tire 810. In other embodiments, wheel 800 can beelliptical or have another substantially symmetrical shape aboutcenterline 809.

In the previous embodiments, rims are shaped so that there is a tangentline tangent to the tire and the sidewall of the rim. In otherembodiments, the rim can be shaped so that there is a tangent linetangent to another point on the rim. FIG. 9 is a diagrammaticrepresentation of a cross section of one embodiment of a wheel 900having a rim 905 seating a tire 910. Rim 905 can be shaped to be widerthan the width of tire 910 at or proximate to the outer edge of rim 905.Additionally, rim 905 can be shaped so that there is a tangent line 915tangent to tire 910 and rim 905. In the embodiment of FIG. 9, tangentline 915 is tangent at the transition 920 from sidewall 925 to tireseating surface 930. Transition 920 is illustrated as being anapproximately right angle corner, but in other embodiments, transition920 between the sidewall 925 and tire seating surface 930 can have othershapes including, but not limited, curves of relatively small radius asshown in the embodiments of FIGS. 3-6.

Wheel 900 is asymmetrical about the centerline of the cross-section ofrim 905 and tire 910 (represented at 935) with the widest part of rim905 (represented by line 940) is offset radially outward from centerline935 of the cross section of the rim and tire. Additionally, nose 945 hasa different radius than tire 910. Consequently, in the embodimentillustrated, the cross-section of rim 905 and tire 910 is notsubstantially elliptical or otherwise symmetrical about centerline 935.

FIGS. 3-9 illustrate embodiments using tubular tires. However,aerodynamic rims can also be formed to seat clincher tires. FIG. 10 is adiagrammatic representation of a cross section of wheel 1000 having arim 1005 seating clincher tire 1010 (two size tires are illustrated,represented by 1010′ and 1010″). Rim 1005 is wider than the width oftire 1010 radially inward from the outer edge of rim 1005. Additionally,rim 1005 can be shaped so that there is a tangent line 1015 (representedat 1015′ and 1015″ for tires 1010′ and 1010″, respectively) tangent torim 1005 and tire 1010. Tangent line 1015 can be tangent to rim 1005 onsidewall 1020, the transition 1025 between the sidewall and outersurface of rim 1005 or at another point on rim 1005. Tangent line 1005can be tangent to rim 1005 at the widest portion of rim 1005 or otherportion of rim 1005. In one example, tangent line 1015 may be tangent torim 1005 further outward on rim 1005 than the widest portion of rim1005, as illustrated by line 1015′, for example.

FIG. 11 is a diagrammatic representation of a cross section of anotherembodiment of a wheel 1100 having a rim 1105 configured for a clinchertire 1110. Rim 1105 can include a clinching portion 1115 for seatingclincher tire 1110. Clinching portion 1115 can be integral with or aseparate component from the rest of rim 1105. According to oneembodiment, clinching portion 1115 can provide parallel braking surfaces(e.g., braking surface 1130).

Rim 1105 is wider than tire 1110 at or proximate to the outer edge ofclinching portion 1115. Additionally, rim 1105 can be shaped so thatthere is a tangent line 1120 tangent to tire 1110 and rim 1105. Tangentline 1120 can be tangent to rim 1105 at clinching portion 1115 orelsewhere on rim 1105. While the cross-section of FIG. 11 isnon-elliptical or otherwise asymmetrical about the centerline of thecross section of rim 1105 and tire 1110 (represented at 1140), otherembodiments of rims using clincher tires can be substantiallysymmetrical or elliptical.

As described above various embodiments of rims can be shaped so that therim and tire form an asymmetrical cross-section. One factor that cancause the cross-section to be non-elliptical or asymmetrical is the noseshape. In the above embodiments, the nose of each rim is shown as beingrounded with a smaller radius than that of the tire. However, anydesired nose shape can be used. FIGS. 12A-12C, for example, illustratevarious embodiments of a nose, including a straight tapered nose 1205, areverse curved nose 1210, and a flat nose 1215 that can cause across-section to be non-elliptical. The embodiments of FIGS. 12A-12C areprovided by way of example and other embodiments of noses can be used asneeded or desired.

Empirical testing has shown reduced drag and increased stall angles forrims according to embodiments of the present disclosure. FIG. 13 is agraph comparing yaw (x-axis) to drag (y-axis) for various wheelsincluding a 2008 model HED Stinger 6 with a 60 mm depth by HED CyclingProducts USA, of Shoreview, Minn. (represented by line 1300) and a 2009model HED Stinger 60 (represented by line 1310). The 2008 Model had arim that was thinner than the width of the tire proximate to the outeredge and had its maximum width near the transverse axis of the wheel.The 2009 HED Stinger 60 was formed according to FIG. 3 having a depth“d” of 60 mm. In both cases a 21 mm tire was used. FIG. 13 illustratesthat the 2008 has a stall angle of about 7.5 degrees while the 2009model exhibits a stall angle of about 15 degrees. Various embodiments ofrims can be shaped to have a desired stall angle.

According to one embodiment, a rim shape is selected so that a tire bedis at least large enough to seat a portion of a tire having a selectedwidth and have a rim width larger than the width of the reference circleat or proximate to the outermost edge of the rim. Additionally, the rimshape can be selected so that there is a line tangent to the tire andthe rim. In one embodiment, the tangent line can be tangent to thesidewall of the rim or other portion of the rim. The line can be tangentto the sidewall at the widest part of the rim or at another part of therim. In one embodiment, the widest part of the rim can be located at theradially outer third of the rim up to the outermost edge of the rim, theradially inner third of the rim or at another portion of the rim. Therim shape can be selected so that the wheel forms a non-elliptical shapeor, in other embodiments, forms and elliptical shape.

The remainder of the rim can have a tapered shape or other shape knownor developed in the art. The rim can be manufactured with a tire bedadapted to receive tubular or clincher tires. According to oneembodiment, a rim adapted to receive a clincher tire can be shaped sothat the tire bead is frontally flush with the rim.

Additionally, embodiments of rims according to this disclosure can beused with disc wheels, traditional spoke wheels, three spoke wheels orother bicycles wheels known or developed in the art. For example, FIG.14 is a diagrammatic representation of one embodiment of a disc wheel1400. Disc wheel 1400 includes a rim body 1405 that can be shaped asdescribed above that is connected to or transitions to an inner disc1410. FIG. 15 is a diagrammatic representation of a wire spoke wheel1500 that includes a rim body 1505 that can be shaped as described aboveand is coupled to a set of wire spokes 1510.

Rims can be used with mountain bike tires or other bicycle tires. Therim can be sized to fit standard size bicycle forks and components orcustom forks or components. The rim can be made from any suitablematerial including, but not limited to, steel, stainless steel,titanium, aluminum, carbon fiber or other materials including metals,composites or polymers and can be formed in a single part or multi-partprocess. The rim can be solid or filled with a filler material.

In the foregoing specification, the disclosure has been described withreference to specific embodiments. However, as one skilled in the artcan appreciate, embodiments of rims and wheels described herein can bemodified or otherwise implemented in many ways without departing fromthe spirit and scope of the disclosure. Accordingly, this description isto be construed as illustrative only and is for the purpose of teachingthose skilled in the art the manner of making and using otherembodiments. It is to be understood that the forms of the disclosureherein shown and described are to be taken as exemplary embodiments.Equivalent elements or materials may be substituted for thoseillustrated and described herein. Moreover, certain features of thedisclosure may be utilized independently of the use of other features,all as would be apparent to one skilled in the art after having thebenefit of this description of the disclosure.

What is claimed is:
 1. An aerodynamic bicycle rim comprising: acircumferential tire mounting surface on a radially outer side of thebicycle rim forming a tire bed to seat a tire; and a set of sidewalls,each sidewall extending radially from a nose of the bicycle rim to acorresponding transition to the circumferential tire mounting surface toform a bicycle rim body having a maximum rim body width at a portion ofthe rim body that overlaps the tire bed, the maximum rim body widthgreater than a maximum width of the tire; wherein, the bicycle rim isoperable to seat the tire so that the cross-sectional shape of the tireand rim body is asymmetrical about the widest portion of thecross-sectional shape and there is a tangent line tangent to the tireand tangent to a sidewall of the bicycle rim radially inward from aradially outermost edge of the rim body having a tangent angle of 8-17degrees, wherein the rim is configured such that a wheel formed by therim and tire has a stall angle of 10-19.5 degrees when the tire isseated.
 2. The bicycle rim of claim 1, wherein the tangent line istangent to the sidewall radially outward from a widest part of thebicycle rim.
 3. The bicycle rim of claim 1, wherein the tangent line istangent to the sidewall at a widest part of the bicycle rim.
 4. Thebicycle rim of claim 1, wherein the bicycle rim is widest radiallyinward of approximately the beginning of the transition between thesidewall and the circumferential tire mounting surface.
 5. The bicyclerim of claim 1, wherein the bicycle rim is shaped so that the bicyclerim and tire form an asymmetrical shape about a centerline of across-section of the bicycle rim and tire.
 6. The bicycle rim of claim1, wherein the tangent line has a tangent angle between 9 and 14degrees.
 7. The bicycle rim of claim 6, wherein the rim is configuredsuch that the wheel formed by the tire and rim has a stall angle of atleast 14 degrees.
 8. A bicycle wheel comprising: a bicycle tire; anaerodynamic bicycle rim seating the tire, the bicycle rim comprising: acircumferential tire mounting surface on a radially outer side of thebicycle rim forming a tire bed to seat a tire; and a set of sidewalls,each sidewall extending radially from a nose of the bicycle rim to acorresponding transition to the circumferential tire mounting surface toform a bicycle rim body having a maximum rim body width at a portion ofthe rim body that overlaps the tire bed, the maximum rim body widthgreater than a maximum width of the tire; wherein, the bicycle rim isoperable to seat the tire so that the cross-sectional shape of the tireand rim body is asymmetrical about the widest portion of thecross-sectional shape and there is a tangent line tangent to the tireand tangent to a sidewall of the bicycle rim radially inward from aradially outermost edge of the rim body having a tangent angle of 8-17degrees, wherein the rim is configured such that a wheel formed by therim and tire has a stall angle of 10-19.5 degrees when the tire isseated.
 9. The bicycle wheel of claim 8, wherein the tangent line istangent to the sidewall radially outward from a widest part of thebicycle rim.
 10. The bicycle wheel of claim 8, wherein the tangent lineis tangent to the sidewall at a widest part of the bicycle rim.
 11. Thebicycle wheel of claim 8, wherein the bicycle rim is widest radiallyinward of approximately the beginning of the transition between thesidewall and the circumferential tire mounting surface.
 12. The bicyclewheel of claim 8, wherein the bicycle rim is shaped so that the bicyclerim and tire form an asymmetrical shape about a centerline of across-section of the bicycle rim and tire.
 13. The bicycle wheel ofclaim 8, wherein the bicycle rim is wider than the maximum width of thetire at the radially outermost edge of the rim body.
 14. The bicyclewheel of claim 8, wherein the tangent line has a tangent angle between 9and 14 degrees.
 15. The bicycle wheel of claim 14, wherein the rim isconfigured such that the wheel formed by the tire and rim has a stallangle of at least 14 degrees.